Produce cooling process



E. H. SPIEGL Filed July 19, 1947 ,//f//f/f/ PRODUCE COOLING PROCESS March 29, 1949.

Parental Mar. 1949 UNITED s'rgrrlzs- PATENT orrlclr;v

PRODUCE COGLING PROCESS Ellis H. Spiegl, Salinas, Calif.

Application July 19, 1947, Serial N0. 782,149 9 claims. (ci. ca -193) My invention relates to means for cooling produce preparatory to shipment and is especially concerned with a process for removing the field heat from produce such as lettuce prior to its shipment to market.

Lettuce is customarily harvested in the ileld at a relatively elevated temperature and is ultimately shipped by refrigerator car transcontinentally to market. Although a refrigerator car is well A insulated and is also often supplied with ice or other refrigerant enroute, it is desirable that the field heat in the lettuce ilrst be removed as promptly as possible in order to enhance the keeping qualities of the lettuce. Often crushed water ice has been packed in the lettuce crates and as a blanket over the lading of crated lettuce in a refrigerator car. but there has been a severe disadvantage in that the sharp corners and spikes on the crushed ice perforate the lettuce leaves permitting the latex to4 ooze out and. oxidize. This necessitates upon arrival at market the removal of the outer several layers of the lettuce headthereby reducing its size and depreciating its market value. At least in part to overcome this diiliculty, I devised sometime since a process for making a refrigerant or coolant in the nature o f a relatively light brine; thatvis, water containing some salt, and likewise containing frozen beads of soft, crystalline, snow-like conformations which were not sharp to the touch and did not bruise the lettuce leaves. This type of material particularly the solids, is sometimes called snowice" and is referred to for example in my Patent Number 2,299,414 issued October 20, 1942.

The standard scheme of shipment has heretofore entailed the use of the snow-ice portion of the refrigerant packed into the lettucecrates intimately with the layers of lettuce heads and then nally, as a blanket layer, over crates or packages of lettuce after they have been installed lnarefrigerator car. l Y l While, in general, the scheme has been reasonably satisfactory, it is an object oi this invention to improve the cooling process.

Another object of the 4invention is to provide a Other objects of the invention, together with the foregoing are attained bythe practice oi my process as exemplied herein. The usually attendant mechanism is' illustrated diagrammatically in the accompanying drawing in which The gure shows a refrigerator car in cross section being supplied with snow-ice and light brine from a schematically represented Source.

While the process has been largely successful with lettuce, and is so described herein, it can equally well be applied to other produce in which similar requirements are posed and in which similar treatment is benecial.

In carrying out the practice of my process the lettuce heads are picked in the ield in the customary fashion and have a ileld temperature of a substantial amount, for example in the neighborhood of to 90 degrees Fahrenheit.

The lettuce heads 6 are packed directly into containers 1 such as crates made up of slats 8 so that there is adequate air circulation around the lettuce heads within the packed containers. These, contrary to normal practice, are originally packed without any ice or other solid refrigerant of any character within the containers.

The previous containers packed with lettuce heads are then disposed in suitable arrangement for free circulation within a standard refrigerator car 9. The car itself is thermally well insulated and is normally provided with ice bunkers ll and l2 for-the reception of solid ice refrigerant to maintain a low temperature within the car during transit.

In accordance with my process, the packed lettuce Acontainers 1 are disposed in the car on the normal slat floor I3 thereof so that there is free air circulation throughout the lading. The produce is then cooled and the ield heat is substantially removed therefrom by pumping or otherwise providing or discharging within the car a coolant, preferably comprising a light brine and snow-ice made in accordance with my mentioned patent. This fluid material is pumped from a container I4 through a iiexible hose line I6 so thatthe coolant is distributed over the top of the lading. The cold liquid, approximately at 32 degrees Fahrenheit, and the snow-ice particles drain or sluice down over the containers and through the pervious sides thereof and in between the lettuce leaves and heads 'to come into intimate contact with the lettuce to extract the heat therefrom.

Some of the snow-ice is in this process melted and it, together with the remaining liquid, drains through the iloor of the refrigerator car and out the drain pipe il thereof. The solid snow-ice i8 remains behind `in the refrigerator car and especially in and on the lettuce heads 6 within the temperature, or if desired, it is returned through an appropriate conduit i8 to the snow-ice manufacturing equipment forremanufacture into further coolant.

While it has been` customary to cool lettuce prior to packing it in'refriaerator cars, and while it has been customary tol cool produce by circu-- lating-air in refrigeratorrcars after the produce has been stored therein, so far 'as I know, it is f new to sluice a liquid -coolant especially a light brine carrying solid snow-ice particles` over packed produce within the refrigerator car prior to shipment. When thisliquid heat extraction step has been carried to a point so that the field heat is substantially ,removed from the produce, the iiexible hose `vIB-or other distributing equipment is removed from the refrigerator car. The car doors areY closed or sealed so that the then cooled produce is contained entirely within an insulated chamber supplied with refrigerant from the bunkers, if necessary, and is then shipped to its destination.A Experience indicates that produce prepared in this fashion arrives at the market in excellent condition and with substantially no exterior leaf damage so that it is readily Salble. K 'j I claim: g

l. A produce cooling process comprising packing the produce in containers pervious to coolant, disposing the `packed vcontainers in a thermally insulated.chamber havinga liquid outlet, discharging a coolant in the .form of snow-ice in a light brine vehicle over said containers, removing the liquid portion of said coolant from said chamber and leaving lthe solid portion of said coolant disposing theapacked: containers in a1 thermallyr insulated` chamber having a liquid outlet, supplying a mixed liquid and solid coolant to said chamber to iilterthroughsaid containers by gravity,

Aremoving spentliquid coolant from lsaid-chamber, thereby leaving solid coolant therein and recirculating added. i

said liquid coolant with solid coolant 4. A produce cooling process comprising disposing produce in a thermally insulated chamber having a liquid outlet, discharging a coolant in the form of snow-ice in alight brine vehicle over v -said produce to lter therethrough by gravity removing the liquid portion of said coolant from said chamber, and leaving the solid portion of said coolant in said chamber.

5. A produce cooling'process comprising packing the produce in containers pervious to coolant. disposing the packed containers in a refrigerator car, discharging a coolant in the form of snow-ice in a light brine vehicle over said containers in said car to iilter'therethrough by gravity, and draining the liquid portion of said coolant from said car.

6. A produce cooling process comprising disposing produce containing iield heat in a refrig- `erator c ar, discharging a coolant in the form of snow-ice in a liquid vehicle over said produce until the eld heat has been substantially removed therefrom, draining the liquid portion oi said coolant from said car, and sealing said car.

7. A produce cooling process comprising disposing produce containing ileld heat in a refrigerator car, discharging a coolant in the form of a cold liquid and solid mixture over said produce until the eld heat has been substantially removed therefrom, removing the liquid portion of said coolant from said car, discontinuing said discharge, and then sealing said car.

8. A lettuce cooling process comprising packing the lettuce containing eld heat in containers pervious to coolant, disposing said packed lettuce in a refrigerator car, discharging a coolant in the form of snow-ice in a vehicle of light brine over said packed `lettuce until the eld heat issubstantially removed therefrom, draining the liquid portion of said coolant from said car, and Y closing said car for shipment.

9. A produce cooling process comprising packing produce containing ield heat in containers pervious to coolant, disposing the packed containers in a thermally insulated chamber, discharging a coolant in the form of snow-ice in a liquid vehicle over the packed containers until the field heat has been substantially removed from the produce, said packed containers retaining snow-ice within said chamber, removing the -remaining liquid portion of said coolant from said chamber, and remanufacturing said removed liquid portion into further coolant.

ELLIS H. sPIEGn REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number I Phillips Apr. 5. 1938 

